Objective To investigate the clinical and imaging features of carotid steal syndrome (CSS), as well as collateral circulation establishment, compensation methods, and outcomes of different treatment modalities, and to provide a basis for the diagnosis and treatment of CSS.Methods A total of 11 patients with CSS who were hospitalized from January to May, 2016, were enrolled. Carotid color Doppler ultrasound, head CT angiography, magnetic resonance angiography, or digital subtraction angiography was performed for all patients to make a definite diagnosis of CSS and evaluate the compensation of collateral circulation. Of all 11 CSS patients, 4 underwent carotid endarterectomy (CEA), 5 underwent carotid artery stenting (CAS), and 2 patients with carotid artery occlusion underwent conservative pharmacotherapy. All the patients were followed up after 3 and 6 months and 1 year of treatment, and ischemic cerebrovascular events and the modified Rankin Scale (mRS) score were evaluated.Results Of all 11 CSS patients, 7 had lesions in the unilateral internal carotid artery and 4 had lesions in the bilateral internal carotid arteries; 7 had a clinical manifestation of transient ischemic attack, 3 had watershed infarction, and 1 had lacunar infarction; 7 patients had posterior circulation ischemia and 4 had anterior circulation ischemia. According collateral circulation establishment on DSA, all 11 patients had primary collateral circulation and 4 also had secondary collateral circulation. According to the ASITN score, most patients had a grade of 3-4. During the follow-up after treatment, two patients who underwent CAS experienced stroke-like symptoms in different periods after discharge, and four patients who underwent CEA did not experience stroke. The patients who underwent CAS or CEA had varying degrees of improvement in the mRS score at 3 and 6 months and 1 year after surgery.Conclusions Patients with severe carotid stenosis tend to develop CSS, with well established collateral circulation, mainly primary and secondary collateral circulation, and posterior circulation ischemia is a common clinical feature of CSS. CEA and CAS can improve carotid stenosis and thus may be used for the treatment of CSS.